Dr. Sonja Mackenzie, DrPH, MSc is an HIV prevention researcher and Adjunct Assistant Professor at the Health Equity Institute at San Francisco State University. Dr. Mackenzie's long-term career goal is to develop a program of research to promote health among sexual and racial/ethnic minority men and women in the United States. The K01 Mentored Research Scientist Development Award will provide the necessary training and mentored research experience for Dr. Mackenzie to successfully become an independent HIV prevention researcher with expertise in mixed methods research and intervention development addressing the cultural and relationship contexts of HIV risk. Dr. Mackenzie's current research findings with bisexually active Black men have indicated the importance of the cultural and relationship contexts of HIV risk and transmission with female partners, and have therefore led her to pursue a dyadic approach. The proposed mixed methods research project constitutes one of the first dyadic investigations of the cultural and relationship context of HIV risk among bisexually active Black men and the female partners of these men. There is an urgent need for effective, culturally appropriate interventions for this community, as bisexually active Black men are highly marginalized. The plan for training and mentorship builds on Dr. Mackenzie's thirteen years of research experience and skills, and will allow her to be uniquely positioned to fill this gap in HIV prevention research and intervention knowledge. In meeting her training goals, Dr. Mackenzie will be able to apply her research expertise with this target population to obtain R01 funding to develop an HIV prevention intervention addressing the specific cultural and relationship contexts of HIV risk among bisexually active Black men. PUBLIC HEALTH RELEVANCE: Black men who have sex with men (MSM), including bisexually active men, are one of the highest risk groups for the acquisition and transmission of HIV in the United States, with prevalence estimates across US cities from 28- 50%. This project proposes one of the first studies of cultural and relationship predictors of HIV risk with bisexualy active Black men and their female partners. As a potential bridge population, developing interventions for bisexually active Black men and their female partners has public health significance.